This article introduces and synthesizes the results of a collective volume on the history of heredity in the Middle Ages. The role of heredity in the medieval West is frought with paradox. Medieval society was largely based on the hereditary – as is apparent from the patterns of transmission of political responsibilities,​ functions, trades, etc. – but this sociological rule was rarely evoked or theorized. A general theory of biological heredity did not exist either. The idea that the mixture of substances provided by the

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parents (seeds, menstrual blood) determines the appearance and sex of the child coexisted, without contradiction,​ with the conviction that environmental and behavioural factors also play an important part. In the life sciences, generation, and not heredity, was the central concept. Emphasis was placed on the individual, and there was little room for thought about the physical characteristics of ethnic groups or other varieties at the sub-specific level. Moreover, Christian discourse insisted on the unity of the human race and rejected the idea of damned peoples or lineages.

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However, the Middle Ages also invented several concepts and terms

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that later played a crucial role in the development of physical anthropology and theories of heredity. The word race, the distinction between noble and non-noble animals (for hawks and dogs) and the idea of noble blood as the metaphorical expression of the Uebermensch status of the aristocracy,​ are all medieval creations. The same is true of the interpretation of the term consanguinity (originally forged by Roman law) in the sense of biological kinship, of the introduction of the legal vocabulary of hereditary transmission in the realm of pathology, and of the explicit distinction between hereditary and congenital illnesses. For the development of discourse about heredity, the 14th century, and especially its first quarter, are

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decisive, initiating a first age of heredity until the rise of current theories of biological heredity in the 19th century. On the other hand, for heredity, the classic divide of 1492 is of relatively little importance.